CVE-2019-15746
📋 TL;DR
CVE-2019-15746 is a critical remote code execution vulnerability in SITOS six Build v6.2.1 that allows attackers to inject arbitrary PHP commands. This enables server compromise and execution of system commands as the web user. Organizations running this specific version of SITOS six are affected.
💻 Affected Systems
- SITOS six Build
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete server takeover with attacker gaining root/system-level access, data exfiltration, ransomware deployment, and persistent backdoor installation.
Likely Case
Web server compromise leading to data theft, website defacement, and use as a pivot point for internal network attacks.
If Mitigated
Limited impact with proper network segmentation, web application firewalls, and minimal privileges preventing lateral movement.
🎯 Exploit Status
The vulnerability allows direct PHP command injection, making exploitation straightforward for attackers with basic skills.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: v6.2.2 or later
Vendor Advisory: https://www.contextis.com/en/resources/advisories/cve-2019-15746
Restart Required: Yes
Instructions:
1. Backup current installation and data. 2. Download latest version from official vendor. 3. Replace vulnerable files with patched version. 4. Restart web server and application services. 5. Verify functionality.
🔧 Temporary Workarounds
Web Application Firewall (WAF) Rules
allImplement WAF rules to block PHP command injection patterns and suspicious parameter values.
# Example ModSecurity rule: SecRule ARGS "@rx (system|exec|shell_exec|passthru)" "id:1001,phase:2,deny,msg:'PHP command injection attempt'
Input Validation Filter
linuxAdd server-side input validation to sanitize user inputs before processing.
# PHP example: $input = filter_var($_GET['param'], FILTER_SANITIZE_STRING);
🧯 If You Can't Patch
- Isolate the vulnerable system in a restricted network segment with strict firewall rules
- Implement application-level monitoring and alerting for suspicious PHP execution patterns
🔍 How to Verify
Check if Vulnerable:
Check application version in admin panel or configuration files. Look for version 6.2.1 in the source code or about page.Check Version:
grep -r "6.2.1" /path/to/sitos/installation/ || find /var/www -name "*.php" -exec grep -l "SITOS.*6.2.1" {} \;Verify Fix Applied:
Verify version is updated to 6.2.2 or later. Test for command injection by attempting safe payloads like 'echo test' in vulnerable parameters.📡 Detection & Monitoring
Log Indicators:
- Unusual PHP execution patterns in web server logs
- Suspicious parameter values containing system commands
- Multiple failed command injection attempts
Network Indicators:
- Unusual outbound connections from web server
- Traffic to known malicious IPs from web server process
SIEM Query:
source="web_server.log" AND ("system(" OR "exec(" OR "shell_exec" OR "passthru") AND status=200